Disposable absorbent articles such as, for example, incontinence products, infant and adolescent care products such as diapers, and feminine care products are generally designed with various layers for performing different liquid management functions. These functions include surge control, distribution of liquids, liquid absorption and retention and liquid barrier. To improve the overall liquid management of these products and other liquid absorbent articles, considerable time, effort and expense have been directed to improving the performance of the materials which are used to form one or more of these layers.
The overall liquid management of an absorbent product may be considered to be the product's ability to not only absorb a liquid but also to transport or channel the absorbed liquid to a desired location within the absorbent article for storage. For example, in products such as diapers and feminine care products, liquid retention at the interface between the body and the product is generally not desired. It is generally desired that such products be designed to rapidly uptake and draw such liquids away from the body/product interface. A material layer which rapidly uptakes a liquid and moves the liquid away from the body/product interface is sometimes referred to as a surge layer or surge structure. Once the liquid has been drawn away from the body/product interface, the liquid is desirably channeled, via a distribution layer, toward and into one or more storage layers. These storage layers desirably hold or contain such liquid while minimizing reabsorption of the liquid by the surge layer. A barrier layer adjacent the storage layer functions to contain the stored liquid within the product.
The storage layer, for example, may be formed from fibers or a combination of fibers and absorbent particles. These fibers may be natural or synthetic. Examples of natural fibers suitable for forming the storage layer include, for example, cellulose fibers, wood pulp fibers, regenerated cellulose, cotton fibers, hydroentangled fluff pulp, fluff pulp, tissue and the like. Synthetic fibers may, for example, be formed from absorbent materials or from one or more polyolefins.
In some instances, the product may be required to withstand multiple liquid insults or wettings before being replaced. As such, the designers and engineers of such products are constantly challenged to develop innovative combinations of materials which not only adequately manage surge, distribution and retention of liquids from an initial wetting, but which also adequately manage liquids from subsequent wettings. The designers' and engineers' tasks are made more formidable in view of the business and economic realities of producing such products for disposable markets. Therefore, there exists a need to manufacture such absorbent articles having improved liquid management capabilities.
Furthermore, some traditional absorbent article manufacturing practices have formed the storage layer from a combination of randomly distributed fibers and randomly distributed absorbent materials. In other words, for example, analysis of fiber and absorbent particle size samples taken across the storage layer would generally indicate that the distribution of large and small fibers and/or particles in these samples is generally uniform. Additionally, traditional absorbent article manufacturing practices have merely loosely combined the variously sized fibers and absorbent particles therein. By merely loosely combining the fibers and absorbent particles within the absorbent article, vibrations, such as shipping and handling induced vibrations, may induce fiber/absorbent particle segregation within the absorbent article. In some instances, such fiber/absorbent particle segregation may decrease the liquid management capabilities of the absorbent article.